Telephone-exchange system



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Patented Sept. 23, 1924,.

UNITED STATES' OTTMAR H. KOPP, 0F BROOKLYN, NE'W YORK, ASSIG-NOR- PANY, mooaronarnn, or

TO TESTER-N ELECTRIC COM- NEW YORK, N. Y., A CORPORATION OF NEW' YORK.

TELEPHONE-EXCHANGE Application filed April 28, 1921.

To all cri/icm t may concern.' I

Be it known that l, Orrin-in H. Korn, a citizen ot the United States, residing at Brooklyn, in the county of Kings, State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following' is a full, clear, concise, and exact description. y

This invention relates to a telephone exchange system, and more particularly, to a system in which machine switching equipment is employed for establishing connections between subscribers lines.

ln systems of the above mentioned character a central oiiice sending' mechanism is employed which controls the selective movements of the mechanical switchingy equipment in accordance with the directory numbers of desired lines, which munbers the callingl subscribers cause to be registered on the registers of the sending mechanism through the operation of .impulse dials associated with the substations ot the lines. A plurality of central oiiice sending mechanisms common to a large number' of subscribers lines lareprovided and an idle one of these senders is selected for the use ot a subscriber immediat-ely following` the removal of the subscribers receiver from its switchhook upon the initiation of a. call.

It after initiating a call the calling` subscriber neglects to dial or only partially dials the number of a desired line and still maintains his receiver olf the switchhook, or due to his line or substation apparatus being out of order the registers of the otlice sender tail to respond to the operations of the calling' dial, or due to trouble in the otlice sender the desired line number is not registered within a. predetermined time, a signal individual to the oiiice sender is operated at a sender monitors position on the trouble desk or" the otlice switchboard. In response to this signal the monitoringl operator first challenges the calling subscriber over an answering` jack associated with the sender to determine from the calling` subscriber, it possible, the cause for the delay in establishing the connection. Il no response is received from the calling subscriber, or il the calling subsiriber responds and it is apparent that the calling` line is in trouble, it

Serial No. 465,294.

is then desirable to connect the calling line with a trunk circuit terminating` at the trouble desk for further observation and until the trouble on the line is clear, and to release the sender so that it may revert to common use, `or it' the trouble appears to be with the particular sender employed to disasscciat-c such sender from connection with the callingY line to permit the calling line to become associated with another sender which is in operative condition.

It is, therefore, the object ot this invention to provide means associated with an oilice sender under the control of an operator to adjust the mechanism of the sender to route a connection from a callingv subscribers line to a trouble desk irrespective ot the setting` which the sender has taken in response to the acts of the calling subscriber.

This object is obtained by the provision of a special jack individual to the office sender and associated with a monitors position on the trouble desk of the otlice switchboard, which jack is connected with mechanism oi the sender in such a manner that upon. the insertion of a cord circuit plug in the jack, the sender is rendered busv and the translator switch of the sender is set to cause the sender to route the connection from the calling subscribers line through the subscribers district selector to a permanent signal trunk circuit terminating' on the trouble deskn i /l`his and other features of the invention may be more readily understood by reference to the following` description considered in connection with the accompanying drawing in which Fig; l shows one of a group or' subscribers lines terminating` in a full mechanical otticev of the exchange, a dia` grammatic illustration of a rotary line switch individual to the subscribers line, a district selector by means of which the calling subscriber may extend connections into various districts and oflices of the exchange, a sender finder individual to the link circuit in which the district selector terminates, a permanent signal trunk circuit terminating in the terminal bank of the district selector and extending to the trouble desk of the o'lice and a diagrammatic reprethe ,calling subscriber in accordance with-l trolling these circuits; Fig. shows registers of Fig. 5 and sentation ot an incoming selector, final selector and called line; Fig. 2 shows talking and signaling mechanism associated with an otiice sender for indicating to a. monitoring operator the progress of the sender in controlling the establishment of the connection together with jacks by means of which the operator may talk with the calling subscribenor set the sender for routinga connection to the trouble desk directly through lthe district selector, and a portion ot' an operators cord circuit for use withsuch jacks; Fig. 3 shows a portion of the control circuits of the otlice sender and a class switch for altering the circuits of the sender in: accordance with the class of the call which isto be established;` Fig. 4 shows a portion of the circuits of the sender comprising a stepping relay, a group of counting relaysy and a sequence switch for conthe code registers ot the sender which are set in accordance with the first two code or otlice designation digits dialed by the calling subscriber and .a steering switch which successively associates the code registers and the numerical registers shown in Fig. (i

with the dialing circuit extending to the vsubscriloers line; Fig. 6v shows the translatorswitch. which assumes a setting' in a'ccordance withi the code set up upon the code which controls the setting ot the class switch of Fig. 3,. and the routing of the desired connection and the numerical registers which are set by the numerical designation of the desired line;l and Fig; 7 is a diagram. showing the man-ner in which the several sheets ot the drawing shouldy be arranged -to show .as

ymuchof 'a complete organization of circuits y asis necessary to disclose the invention.

The calling subscribers line C is` ot the usual'l type provided with a transmitter, receiver and call bell and since it terminates in an automatic exchange, it is also equippedv The incoming and with an impulse sending dial S of the usual type.

The subscribers line C terminates in an individual. line switch of the well-known step-by-step type. In order to simplify the drawing only the wipers of the switch have been` indicated. l

rl`lie district selector disclosed in Fig. 1 isof the general type shown in the patent to E. B. Craft and J. N.. Reynolds 1,123,- 696, issued January 5, 1915. To simplify the drawing, only one of the tive brush sets and a. portion of the corresponding terminal bank of this switch have been disclosed. iinal selectors and are of this same type but have been disclosed only diagrammatically herein. The sender finder SF, Fig. 1, the sender monitors time measure switch M shown in Fig.

2, the register steering switch RS and code registers A and B, Fig. 5, and the numerical registers TH, H, T and ll and the translator switch shown in Fig. (i, are of the well-known step-by-step type. With the exception of the sender linder SF and the translator TS, the wipers of these. switches are restored by being advanced by their respective stepping magnet-s forwardly to normal position. F indcr switch SF and translater switch TS have no normal position, the wipers thereof resting in contact with the setting of bank terminals last employed by the switches.

For controlling the circuits associated with the district selector and the circuits of the office sender, auxiliary switches are employed. These switches may be ol the type disclosed in the patent to J. N. Reynolds and C. F. Baldwin 1,127.8()8, issued February 9, 1915 and known inthe art as sequence switches. The permanent signal tiunk shown in Fig. 1 and the monitoring opcrators cord circuit diagrammatically illustrated in Fig. 2 are ofi the type fully disclosed and described in the application of Edward F. Trapp. Serial No. 427,791, filed December 2, 1920. The different pieces of apparatus employed in illustrating the manner in which the invention is to be practiced having now been briefly described, it is thought that a clearer understanding of the invention may be had from a description ot' the manner in which a calling line may be connected tc the trouble desk.

Initiation of (i.v call by the call/ing .wbwrbmu It will .first be assumed that the calling subscriber removes his receiver from its switchhook properly dials a desired number and. that the connection is con'ipletely established in the proper manner. Tipon the rcmova.'l ot his receiver from its switchliook, a starting circuit is established for the line switch 100 in the manner 'fully set foi-tb in the application olf F. A. Stearn. Serial No. iti/1,242, tiled April 199.1, and switch 10U starts limiting 'lor an idls` link crcuit. The test terminals ot busy link circuits are ren-- dei'ed busy by ground potential on the multiples ot' the test tern'iinals 11i of such link circuits connected thereto through armature contacts of sleeve relays corresponding to relay 101, or through the contacts of sequence switch cams corresponding to cani 115. As soon as the test wiper ot switch 100 encounters the test terminal 114 et :in I:dle link circuit, which link circuit will be as suined to be the one disclosed in Fig. l. battery potential will be encounteredk and. the line switch 109 will stop with its wipers in engagement with the bank terminals con-- nected to such idle trunk. Battery potential is connected to the test conductor 11-4 through the left-hand armature and normal contact of relay 101 and the contacts of cam 113 (1).

Upon the seizure of the link circuit terminating in the district selector 150, a circuit is established tor sleeve relay 101 or" the link which maybe traced -lfroin battery through the winding of relay 101, the nor-` mally closed contacts associated with the lett-hand armature of relay 102, the lower contact of cam 103 (1 to 2%), bank terminal 1041- and wiper 105 of line switch 100 and to ground through the winding oit cutoil" relay 106. Relay 101 energizes in this circuit and establishes a circuit for line relay 107 or the district selector 150, which circuit extends l'rom battery through the right-hand winding ot relay 107, the lower contact ol" cam`108 (1), the lower contacts: of cam 109 and to ground through the righthand armature and alternate contact oit relay 101 and the lower contact of cam131` (17 to A t the'alternate contact of its left-hand armature, relay 101 connects. ground potential to the multiples ot test terminal 114- to mark the link circuit as cbusy7 to other line normal contact ot this armature disconnects the source of battery potential which up to the time the link circuit is seized marked the link as idle7 Relay 107, upon energizing, closes a circuit for driving sequence switch y110 out of its normal position 1, into position 2, thiscircuit extending from battery through themagn'et winding of the switch, the upper left-hand contact of cam 111 (1), the inner right-hand armature and alternate contact of relay 107 and to ground at the right-hand Contact of cam'112 (1 to 6). Under the control of master cam 180, the sequence. switch is driven into position 2, in which position` a circuit is closed from battery' through the left-hand winding ot difieren-- tial relay 102 and thence to ground at the upper lett-hand contact of cam 115 (2 to 11). Relay 102, upon energizing, closes ay locking circuit for sleeve relay 101 extending through the winding oi relay 101, the" make contact of the lett-hand armature oit' relay 102, the upper contact of cam 103 (1% to 16), and thence as 'previously traced from yground through the winding of cut-oli relay 106, this circuit being maintained through position 16 of the sequence switch or until relay 102 becomes Adeenergized. Upon reaching position 2, the sequence switch connects a new holding ground to test terminal 114:, through the upperrighthand contact of cam 115 (2 to 18%).

As soon as the sequence switch reaches position 1%, a circuit is closed for the stepping magnet 116 of the sender Finder Sli" extending vfrom battery through the interrupter contacts and winding ot' magnet 116, conductor 117 the lower lett-hand contact` switches and at thel of cam 118 (13,4: to2), the inner right-hand armature and alternate contact of relay 107 and thence to ground at the right-hand contact oil cam 112. A. circuit is also closed at this time through the 'winding' ot stepping magnet 116, the winding or relay 123 and thence to ground at the lower left-hand contact of cam 115 (2 to 11). Relay 123 does not energize at ths time, however, since its winding is shunted by ground connected through the armature and contactolf relay 107. As soon as the sequence switch 110 leaves position 1, the initial energizing circuit of relay 107 is opened at the lower contact o1 cam 108, but this relay remains locked over a circuit extending .troni battery through its left-hand winding, lett-hand armature and alternate contact, the upper left-hand contact orp cam 119 (1 to 6), the lower contact of cam 120 (1 to 21,41), conductor 121, test wiper 122 and to ground on busy terminals of the bank over which this wiper moves. its soon, however, as an idle sender mechanism "found, the wiper 122 will tind no ground potential on the terminal corresponding to such idle sender and line relay 107 will thereupon deenergine, opening at its inner right-hand armature and alternate contact the circuit extending through thc stepping magnet 116 and closii'lg at the normal contact of this armature, a circuit for driving sequence switch 110 out of position 2 and into position 3. This circuit may be traced from battery through the magnet winding' of sequence switch 110, the upper right-hand contact ot cam 111 (2), the inner righthand armature and normal contact of relay 107 and thence to ground at the right-hand contact of cam 112.

As soon as line relay 107 deenergizes, the .shunt around the winding of relay 123 is removed at the inner rigl'it-hand arniature and alternate contact olil relay 107 and relay 123 encrgizes in series with stepping magnet 116, the current tlowing through this circuit, however, not being sutticient to cause the energization ot magnet 116. At 'the normal contact of its left-hand armature, relay 107 connects busy ground potential to the wiper 122, over conductor 121, the lower contact of cam 120, lthe upper left-hand contact of cam 119, the armature and contact of relay 107 and to ground through the lower contacts of cam 112, which busy ground potential is maintained until the sequence switch passes out oll position or until relay 123 has time to energize and connect busy ground potential to the wiper 122 over .its inner left-hand armature and :alternate contact.

Relay 123, upon energizing,`in addition to connectingground potential to the wiper 122, establishes a circuit extending over wiper 122, conductor 300, the lower right hand and upper fleftdia'nd fcontacts of cam 301 and to ybattery through the winding of relay l302. Relay 302, upon energizing, closes a loclring circuit for itself extending through its inner right-hand armature and alternate contact xto vconductor 300 independent of the vcontacts ot 'cam 301 and at its lett-hand armature and alternate Contact establishes -a circuit tor advancing class se'- quence switch 306 vout of position 11, and under the in'fiuenceoi` master cam 321, into fposition This circuit may be traced trom battery 'through the magnet winding 'of switch `306, the upper right-hand contact of cam 305 `(.1), conductors304 and 303 Aand to grou'nd'atthe rightlhand armature and normal'contact of relay 325.

Relay 123, upon energizing, also estab lishes an impulsing circuit Lextending from the calling subscribers line to the controlling relays of the 'register' steering switch RS which may be traced from battcry through lthe winding of relay 307, `conductor 200, conductor 303, wiper =163 or "switch SF, conductor f161,conductor 165, the Iletthand'contact ot cam A166, bank 'terminal 131 and 'wiper 182 `ot 'the line switch '100, `thence over the calling 'subscribers line loop and through his impulsemechanism S, wiper '133 and bank terminal 184 'of switch 10U, the left-hand `contact 'of cam 160 (2 to 101,421), conductor '161, wiper 162 of the switch SF, Vconductors 309 and 202 and to rground through Ithe left-hand winding 'of coil 310. Relay 307 energizes in thisfcircuitand yestablishes 'a circuit Jfor the slow-tto-release lrelay 312 extending from battery Athrough the winding of 1rela-yi312, conductor 311 iand =to ground at lthearmature contact of relay 307 and relay 312, upon energizing, establishes an obvious `circuit for relay 4313. lith 4relay 313 energized, the source-ofdialingtone 314 fis inducti-vel-y associated through Ithe right-'hand'winding of coil 310 with the impulsing circuit previously y'traced v-or transniitting a. -dialing tone to the calling subscriber to indicate to the subscriber that a sender lhas Vbeenassociated with his `line and is in readiness to receive impulses icorrespondingto lthe number ofthe iline desired. This tone circuitmay vbe ytraced from ground through the'secondary 1winding'otthe tone coil 326, the right-hand vwinding otcoil 310, conductors-315 and 316, wiper "500 and the normalterminal of baril: A1 of'code register A, vconductors 501 and l502 fand thence to ground at lthe'left-hand armature and vnormal contact of relay 503.

As soon as the otiice sender is seized and theclass'sequence switch 306 moves outfot position 1 and into position3, acircuit is established 'for starting the time measure mechanism at the monitoring position of the vtrouble Vdesk to measureott a'time period suliicient to allow the'calling subscriber to com-plete dialing. This starting circuit may be traced from ground through the contact of cam I321 `(12%z to 18), conductors 320, 3139, 318, 317, 213 and 212, the armature and normal contact of relay 215, conductors 211, 210 and 200, wiper 208 and thc normal terminal of bank M2 of switch M, 'conductor 207, the slow speed interruptor 206, conductors 205 and 2011, and thence to battery through the winding of relay 203. Relay 203 energizes in this circuit as soon as interrupter 206 reaches a circuit closing position and closes a locking Acircuit for itself extending from battery through its winding, over conductor 2M, through the winding of relay 215, conductor 216, the armature `and contact ot relay 203 and thence to conductor 212 and ground at the contact of cam 321 as previously traced. Relay 215 does not energize in this circuit until the interrupter 206 reaches an lopen position. Vhen Delay 215 does energize, a circuit is prepared for relay 217 which is effective as soon as intcrrupter 206 again reaches a circuit closing position. This circuit for relay 217 may be traced from battery through the winding ot' relay 203, conductors 204 and 205, in terrupter 206, conductor 207 the normal terminal of bank M2 and Wiper 208 of switch M, conductors 209, 210 and 211, the armature and alternate contact of relay 215, conductor 218, the winding of relay 217, conductor 216 and thence to ground on conductor 212 through the armature contact of relay 203. Relay 217, upon energizing, closes a locking circuit for itself extending from battery'through the Winding of relay 203, conductors 214 and 219, the left-hand armature 'and contact 'ot relay 217, conductor 211, the armature and alternate contact ot relay 215, conductor 213, the winding 'of relay 217, conductor 216, the armature and contact of relay 203 and thence t'o ground on conductor 212.

At its right-hand armature Contact, relay 217 establishes a circuit, for relay 222 which may be traced from battery through thc winding of relay 222, conductor 221, thc inner right-hand armature and normal contact ot relay 232, conductor 220, the righthand armature and contact of relay 217 and to ground on conductor 212. Relay 222 now establishes a stepping circuit for advancing the switch M under the influence of the slow in'terrupter 206 which may be traced from battery through the winding of steppingr magnet 223, conductors 224 and 225. the left.- hand armature and alternate Contact of relay 222, conductor 205, interrupter 206, conductor 207. the strapped terminals 1 to 6 ot bank M2 wiper 208, conductor 209 and thence to ground at the alternate contact of the outer right-hand armature of relay 222. During;r the successive operation of rclays 203, 215, 217 and 222 and the advance of the switch M from normal position through. position 6, sullicient time is measured to enable the calling subscriber to dia-l the desired number. It at the time the switch M reaches posit-ion 7 the number has not been dialed, the switch M stops in position 7 since its circuit is interrupted at the Wiper S and a circuit is established for the sender lamp 226 which may be traced from battery through the lamp 226, conduc- 'tor 227, the No. 7 terminal v.228 ot the bank M", Wiper 229, conductors 230 and 231, conductor 508 and thence to ground at the armature and alternate contact of relay 504. Relay 501i is energized at this time since a4 circuit Was established through its Winding` upon the energization ot' relay 313, which circuit extends from battery through the Winding of relay 5011, conductor 505, the normal bank terminal of bank R51, Wiper 506, conductor 507 and thence to ground at the alternate contact of the inner right-hand armature of relay 313.

lt at the time switch M reaches position 7 the steering switch RS has lett normal position, that is, a part of the desired line number has been registered and the sender sequence sivitch 4100 has not -left normal position, or is Waiting for the completion of registration in either positions 9 and 17, the lamp 226 will be lighted dimly through the Winding of relay 563 and the connection to interrupter 513 or direct ground at relay 504: will be interrupted at the armature cont-act of relay 563. It sequence switch 1100 is in position 1,'the circuit for relay 563 may be traced from ground at the inner right-hand armature ot relay 313, conductor 507, Wipe 506, the No. 1 terminal of bank R81, conductor 472, the upper contact. of 'cam 1:70, conductor 1171, the lefthand winding ot relay 563, conductor and thence to battery through the lamp 226 as previously traced. lilith sequence switch +100 in either position 9 or 17 the circuit of relay 563 may be traced trom ground at the inner lett-hand armature ot relay 313, over conductor 565, the loiver contact of cam 470 and thence to battery through lamp 226 as previously traced.

lli, the register steeringswitch. RS has moved ott normal and sender sequence switch is in any position other than positions 9 and 17 the lamp 226 will be flashed over the circuit. previously traced to the armature and backcontact of relay 563, conductor 508, the 'armature and normal contact of relay 504 and to ground through the. tast interrupter 513. In response to either a` bright, dim or flashing signal on lamp 226, the operator at' the monitors position challenges the calling' subscriber in a manner to be hereinafter described.` lt will first be assumed thatthe calling sub scriber proceeds within the required time interval to dial the digits ol the desired number and that the calling subscriber desiring' a connection with a line Whose directory number is O A kland 3612 proceeds first to dial the code letters O A to set the registers A and B.

Setzt/ng Hte code registers.

ister A, conductor 510, Wiper 509 and the normal terminal ot' the bank RSZ, conductor 323, conductor 322 and thence to ground at the armature and back contact ot stepping relay 307. Relay 503 is sloW-to-release and maintains its energization during the transmission ot' the series ot impulses through the Winding ot stepping magnet 511 and upon its initial energization opens at its lett-hand armature contact the circuit previously traced over which dialing tone was transmitted to the calling subscribers line. During the energization ot stepping magnet 511 ot the register A, relay 514 energizes in parallel With the Winding ot' relay 511 over a circuit Which may be traced from battery through the Winding of relay 514, conductor 515, Wiper 516, the normal terminal of bank RSS, lead A, the oli-normal terminals ot bank A2 ot the A register as soon as this register advances out of its normal position, conductor 518, the armature and contact ot magnet 511, conductor 510, the normal terminal of bank RSg, Wiper 509 and thence to ground on conductor 323 at the armature and back contact ot stepping relay 307. Relay 514; energizes in this circuit and closes a locking circuit tor itseltl independent ot the armature contact oit relay 307, which circuit extends over the circuit previously traced through the Winding ot relay 514, through the armature and back contact oli' magnet 511, conductor 323 and thence to ground at the right-hand armature and contact ot relay 514. Relay 514; and stepping magnet 511 are thus maintained energized over this circuit until the stepping magnet 511 has moved its armature to substantially the tall extent of its movement When the circuit through relay 514e is opened at the armature contact oit magnet 511. Relay 5111 thus insures that the stepping` magnet 511 will operate to the full extent of its movement upon each energization thereof. At its lett-hand `armature and front Contact, relay 51A- closes a circuit over conductor 519 for maintaining the sloW-to-release relay 312 energized during each step of the register A irrespec` tive of the operation ot stepping relay 307.

conductor 328, the upper ductor 603, Wiper vUpon the completion ping impulses through net 511 of the. register A, relay 503 deenergizes and at its left-hand armature and normal contact establishes a circuit for relay 519, which may be traced from ground at the left-hand armature and back Contact ct relay 503, through the Winding ot' relay 510,

lett-hand and lou'- er. right-.hand contacts off cam 327, conductors 523; and 6,07, Wiper 60,6 and normal terminal of `bank Ul of the units register U, conductor 605, Wiper 6.04; and normal terminal of bank( T1 out the tens register T, con- 6102 and normal' terminal of bank H1 of hundred register H, conductor 601, Wiper 600 and normal terminal ot bank- THl of the thousands register TH, conduct-or. 522, Wiper 521 and the normal bank terininalof the'bank B1 of the code register B, conductor 5,20, Wiperl 517 and the oit-normal terminals ot` the bank A2` of the code register A, lead A, Wiper 516 the steering switch RS, conductor 515 and through the Winding ot relay 5,14; to battery. Atits outer lettehand armature and alternate contact relay 51,9 closesI a circuitfrom ground, over conductork 5,28, through i'viper 527 in contact With the normal terminal ot bank Re?, conductor 526, the right-hand armature and back contact of relay 503, conductor 525, and thence to battery through the armature contact and Winding ci' stepping magnet 524` of the steering switch RS. Magnet 524. energizes in this circuit and advances the `wipers of the steering switch into contact with the No. 1 terminals oit the banks with Whichthey are associated, the circuit ofA magnet 5211 being opened at the normal terminal of bank RS4 as soon as the steer-ing switch leaves normal position. With thesteering switch RS, in position 1, a circuit is established for the stepping magnet 530 of the code register B which may be of the series of stepthe Winding of magtraced from battery through the Winding of relay 50.3., conductor 512, Winding of magdialed by net 530, conductor 529, the No. 1 terminal of bank RSZ, Wiper 509, conductor 323, the outer left-hand armature and front contact of relay 313, conductor 322 and to ground at the armature and back contact of relay 307, and magnet 530 in response to the suc: cessive deenergizat-ions ot' stepping relay 30.7 in accordance with the code letter A the calling subscriber advances the Wipers of the code register B into position 2. Each time the impulsing circuit is established through the Winding of magnet 530, a circuit is established for relay 514C extending Jfrom battery through the Winding otrelay 514, conductor 515, Wiper 516, the No. 1 terminal of bank RS?, lead B, the arma ture and back contact of magnet 530, conductor 529, and thence over. the circuit previously traced togroundat the armature and back contact of stepping relay 307. In the manner previously described, relay 514 insures that the magnet 530 will be completely operated to cause the wipers of register B to be advanced a ull step upon each'ener gization of magnet 530.

Following the completion of the second series of code` impulses, relay 503 deenergizes as previously described and again establishes the circuit of relay 519k which may be traced over the circuit previously described to conductor 522 and thence through wiper 521, the oil-normal terminals of bank B1 of code register B, lead B, the No. 1 terminal of bank RSS, Wiper 516 and thence to battery through the Winding of' relay 514. Relay 519., upon energizing, closes ay circuit for advancing the register steering switch BS. out of position 1, into position 2. The circuit of magnet 524 for advancing switch RS may be traced at thistime from battery through the Winding and armature contacts of magnet 524, conductor 525, the righthand armature and normal contact of relay 50.3, conductor 526, Wiper 527 and the No. 1 bankr terminal of the bank RS, conductor 531 and thence to ground through the offnormal terminals of bank B2 of code register Pv and Wiper 532.

As soon as the steering switch RS reaches position 2, a circuit is established for relay which may be traced rom battery through both windings of relay 533, conductor 534, the No. 2 terminal of bank RS, Wiper 506, conductor 507 and thence to ground at the alternate contact of the inner right-hand armature of relay 313. Relay 533, upon energizing, locks through its righthand armature and alternate contact to ground at the contact of cam 321, over conductors 319 and 320, and at the contact of its inner left-hand armature establishes n circuit for advancing the translator switch TS, Fig. 6.

Setting the translator switch and Claas switch.

The circuit for advancing the. translator switch may be traced from battery through the normally closed right-hand armature contacts of relay 535, conductor 536, the armature contacts and Winding of stepping magnet 608 of, the translator switch TS, conductors 6.09 and 537 and thence to ground at the inner lefthand armature contact of relay 533. The translatorswitch under the influence of stepping magnet 608 advances its Wipers until one of the test Wipers 610 or 611 encounters a bank terminal upon which testpotential has been placed through bank terminals and Wipers of the code registers A and B, when a circuit is closed for relay 535. In the case assumd, 00de register A has been set in position 6 and the code register B. has been set in position 2 and, therefore, the circuit of relay 535 may be traced from battery through the normally closed right-hand armature contacts and low resistance left-hand winding of relay 535, conductor 538, wiper 539 and bank terminal 540 of bank A3 of register A, conductor 541, wiper 542 and bank terminal 543 of bank B5 of register B, conductor 544, test terminal 613 and test wiper 610 of translator switch TS, the armature and normal contact of switching relay 614 and thence to ground at the armature contact of relay 533, over conductors 609 and 537. Relay 535, upon energizing in this circuit, opens the operating circuit of stepping magnet 608 at its right-hand armature contacts and removes the shunt from around its righthand high resistance winding, so that relay 535 is maintained energized in t-he circuit previously traced through both of its windings.

Had the first code letter been R instead of O, then the code register A would be standing in position 7 and the switching relay 614 would therefore be energized over a circuit extending from battery through its winding, conductor 615, terminal 546 of the bank A4' and to ground through wiper 547 and, therefore, the test wiper 611 would be employed for testing purposes rather than wiper 610. Thus, through the employment of switching relay 614 and the division of the banks of the translator switch TS into two sections, the translator switch is given access to twice the number of bank terminals without increasing the extent of movement of the wipers ot the switch. Banks B3, B4 and B6 of the code register B are cross connected to test terminals in the banks TS1 and TS2 oi. the translator switch TS as desired to enable the translator switch to assume various positions corresponding to combinations of positions assumed by the code registers A and B. f

The translator switch is now set in the proper position for controlling the class switch 306 and for controlling the district brush, district group, oiiice brush and otlice group selections required to attain access to the othce desired, which, in the case assumed is the() A kland oilice, or a mechanical office requiring the setting of the class switch into position 7.

Upon the energization of relay 535, a circuit is closed to advance the class switch 306` ont. of position 3 which may be traced through the magnet winding' of switch 306, the lower left-hand contact of cam 305 (3 `to 15), conductor 330, the left-hand armature and normal contact of relay 329, conductor 331 and lthence to ground at the alternate contact of the outer left-hand armature of relay 335. The class switch 306 continues to advance until class relay 329 becomes Venergized. Upon the class switch reaching a position corresponding to the class sett/mg of the translator switch TS, if it be assumed that the switch TS has been set in position 4 for routing a call to the O A kland oilice, then when class switch 306 reaches position 6% a circuit is established for relay 329 which may be traced from battery through the winding of the relay, the upper letthand and lower right-hand contacts of cam 332, conductor 333, terminal 616 ot' bank TSG, wiper 617, conductor 618 and thence to ground at the alternate contact of the inner .lett-hand armature of relay 535. Relay 329, upon energizing, closes a locking circuit for itselfl extending through its winding and the cont-act of its inner right-hand armature to ground through the lower contact of cam 338 (4 to 17), and at the normal contact of its right-hand armature opens the circuit previously traced over conductor 213, whereupon relays 215 and 217 become deenergized and the counting of time by switch M is stopped. Upon the removal of ground potential from conductor 213, relay 232 becomes energized in series with relay 222 over a circuit extending from battery through the winding of relay 222, conductor 221, the winding of relay 232, the strapped bank terminals of bank M1 of switch M, to ground at wiper 234, it being assumed that wiper 234 has been advanced through the operation of stepping magnet 223 to some position between its normal position and position 7.

Upon the energization of relay 232, a restoring circuit is established for the switch M `which may be traced from battery through the winding of stepping magnet 223, the armature contacts of this magnet, conductor 235, the inner left-hand armature and contact of relay 232, conductor 236,

the inner right-hand armature and contact of relay 222, conductor 237, the strapped bank terminals of bank M1 of switch M and to ground through wiper 234. As the wipers of switch M pass position 7, the circuit of sender lamp 226 is maintained open at the outer right-hand armature and contact ot relay 232, so that the lamp 226 is not operated. As soon as the wipers of switch M reach position 8, the circuits previously traced through the windings of relays 232 and stepping magnet 223 are opened and wiper 234 of the switch M is arrested with its wipers standing in position 8, which position is a normal position for the switch.

Relay 329, upon energizing, also closes a circuit for advancing the sequence switch 400 ot' the oliice sender out of position 1 and into position .2` preparatory to controlling the district selector in its brush selection movement. This circuit may be traced from battery through the magnet winding of switch 400, the upper right-hand contact of cam 401 (1), conductor 402, the left-hand armature and alternate contact of relay 329,

`ping relay 407 again energizes. Thus, during the upw'ard movement of the switch shaft, the sender stepping relay 407 is intermittently energized and deenergized.

Under the assumption that the translator switch has been set into position 4, a circuit is established upon the first energization of `stepping rel-ay 407 following the establishment ot the fundamental circuit, which may be traced from battery through the No. 2 counting relay 414, the armature and normal cont-act of the No. 2 counting relay 415, lead 416, Fig. 6, terminal 627 of bank TS3 ot :the translator switch, wiper 623, conductor 629, class switch cam 339, conductor 340, the upper left-hand Contact of cam 417 y(2), the lower right-hand contact of cam 418 (2), conductor 419, conductor 420, the normally closed contacts associated with the outer left-hand armature of relay 421, the upper contact of cam 422 (1 to2), the armature contact of stepping relay 407, conductor 423 and thence to ground through the upper contact of cam 413 (1 to 2). Counting relay 414, upon energizing in this circuit, closes a locking circuit for itself extending from battery through its winding, the winding or counting relay 415, the armature and front contact of relay 414, the upper contact of cam 424 (2) and thence to ground on conductor 425. Counting relay 415 does not energize, however, until relay 407 deenergizes at the time the wiper 123 or the district selector engages` the first conducting portion of segment 129. Upon the energization or" relay 415, the lead 416 is extended `throughthe armature and alternate contact of relay 415, the armature and normal contact of 'the No. 1 counting relay 427 and thence to battery through the winding ot the No. 1 counting relay 426. Upon the second deenergization of stepping relay 407, relay 427 becomes deenergized and connects Vlead 416 to the No. counting relay 428 and` in response to the next deenergization of stepping relay 407, the N o. 0 counting relay 429 is; energized, closing a circuit for driving sequence switch 400 out of position 2 and into position 4. rllhis circ-uit may be traced from battery through the winding of sequenceswitch magnet 400, the lower righthand contact of cam 439 (2), the left-hand armature and normal contact of relay 436, conductor 440, the inner right-hand armature and normal contact ot relay 421, conductor 441 and thence to ground at the armatureand contact or the No. 0 counting relay 429.

Sequence switch 400 upon leaving position 2 opens the locking circuits of all counting relays which have been locked up at the right-hand contacts of cam 424 (2). At the time the No. 0 counting relay 429 energized in response to the last deenergization of stepping relay 407, relay 409 `the updrive magnet is energized in parallel therewith, opening at its armature and back contact the previously traced fundamental circuit extending through the windings of stepping relay 407 and control relay 107 of the district selector 150. As soon thereafter as theiwiper 128 engages the next insulating portion of segment 129, the circuit of relav 107 is opened and this relay deenergizes, closing a circuit `for driving the district selector sequence switch v110 out of position 4 and into position 5, this circuit extending from lbattery through the magnet winding of sequence switch 110, the upper right-hand contact of cam 111 (-1-), the inner right-hand armature and baclr Contact of relay 107 and thence to ground at the right-hand con-tact of cam 112. As soon relay 107 d'eenergizes the circuit previously traced through 126 is openedatthe inner right-hand armature and vfront contact of relay 107 and the upward `movement of the switchl shaft is arrested. lllVith"sequence switch 110 in position 5 and the sender sequence switch 400 in position`4, the 'fundamental circuit previously tracedis again established and relays 107 and 407 again energize. Relay 107, uponV energizing, causes the movement or the district sequence switch 110 fromY position 5 to `position 6, the initial energizing circuit of relay 107 being opened as previously described at the upper right-hand contact of cam v119 as soon as the sequence switch leaves position 5, but relay 107 remaining energized over the fundamental circuit through its rleft- .hand winding and the front contact of its left-hand armature andthe left-handcontacts or cani 119.

As soon as the sender sequence switch 400 reaches position 3, a circuit is established through the right-hand winding of relay 102 at the district selector'which may he traced from battery throughthe winding of relay 102, the upper'right-liand contact or cam 146 (1 to 10), the 'outer right-hand `armature and front contact of Arelay 123, the

lower contact offcam 147 (3 to 10),'wiper 143 of switch Sl?, conductor 341, conductors 342 and 343, resistance element 344, conductor 345 and thence'to ground on conductor 425 through the upper contact 'of sender sequence swich cam 430 (4 to 18). Relay 102 is differentiallywound, but due to the inclusion of resistance element 344 Vin the circuit of its right-hand winding the current llowing through the right-hand winding is not suticient to diilerentially release the relay. As soon as sequence switch 110 reaches position 4, relay 145 becomes energized over a branch of the above vtraced circuit extending through the upper left-hand contact oic cam 146 (4 to 10) through the winding or relay 145 to battery. Relay 145, upon energizing, preparesy a circuit for en- 110 yover a circuit extending trein trout contact' ot relay ylower right-hand contact ot' cani 115 (if as .the switch sha'lt approaches Iinent 133, the shunt circuit is opener*L lay /107 is intermittently energized and ergizing relay 10? when sequence switch 110 reaches position 9 as will be hereinatter described.`

Af Distr/ct group solco-tion.

y As soon as sequence switch 110 reaches position 6, the circuit previously traced for the updrive magnet 126 oit the district selector is again established through the right-hand Contact ot earn 113 o) and the vinner right-hand armature and iront Contact of relay 107 and in the inanner previously described switch shalt 12?' is again driven upwardly. clince at this time, however, the tripping spi dle 13G has been rotated by the tripping magnet which was energized in position 5 sequence switch battery through the winding olf magnet 13S and thn 7), the Vthird set of brushes is no w tripped upon the initial upward nieren ont ot switch shaft 12'? and during the continued upward movement ot the shaft the brushes travel over the hanlr with which they are associated. rlhe remaining 'four or brushes on the switch shaft are not tripped at this time 'and are, therefore, iunctionless. its tiretgroup selection position, wiper 132 engages the iirst metallic portion ot the group selection segment 133 ot the ooininutator and a circuit is closed in shunt ot the winding ro1' `the sender stepping relay L10T which may be traced 'iroin battery through the leithand winding, lett-hand armature and 10T,v uppcr lett-hand and lower right-hand contacts o'i cani 110, Aconductor 134e, seginent 133, wiper 132 and thence to ground at the right-hand Contact ot cain 131 (9 to 7.) Relay 10i' 's inaintained'energiZe-:l over this circuit and the sender Stepping relay 10? becomes deenen gized. As the switch shaft continues in its upward moveinent and the wiper 132 engages the lire insulating` portion seg ain sender stepping relay 1107 again energizes. 1n this manner during the 'lurther in Venient ot the switch sha'it in its group selection. movement, the sender stepping,` re- Ideenergized. l

Upon the iirst energization ot stepping` relay 4F07 a circuit is closed ior the lio. 0 counting relay 1i-23, it being,` assumed that the calling siufosm f r has dialed such a code as to set the translator switch into position 1. rhis circuit inay be traced iroin battery through the winding oi relay lead 131, lead 131 Fig. 0, terininal 030 ot haul: Till or the translator switch, wiper G31, conductor 632, the contact oiC class switch cani hand contact ot cani 113 (4f), conductors 119 and 120, the lower contact or cani to the armature contact oi relay 40T, conductor and thence to ground through the lower contact of cani 113 (3 to Counting; relay L123, upon energizing, closes loclting circuit 'tor itself extending 'through the g ol'i the No. 0 cminting f the miniature :ind Yfront 3 and thence to ground upper contact ot cani l2-1 (el). ilrst. deenerp'ination ot stepping relay dit; energizes in parallel l" and closes at its urn'lature and contact circuit 'tor advancing` '00 out o1 position 1. This ccd troni battery through i ouencc switch A100, the lett-hand urinaH norinnl con ,1 et relay 130, concondnc'ror -jlfl-l and thence, to 'zturc contact olf relay 121). ion l1 the locliing circuit Y, the windings ot thc and iLl is opened :it the contact' ot and these relays therei V)on decner lielaj; 100, upon energiz roinlaiuentul circuit at its ,lach contact thereby causing.,r

i oif line relay 107 of thc as soon as wiper 132 enisulai ing portion of segment i lay 10i', pon deenergiaing, opens at its right-hand arinutiu'e and l'ront contact w'iously traced circuit o1 the 11p-drive 'l 0 thereby :xrrez'slinfg` the upward or the switch shatt Yfor positionti'ipped set olf brushes on the lirst set the iiist group oli terminals its inner right-halid arinaiacl; contact relay 10T closes the reifionsly traced circuit tor driving; se t switch 110 ont o1 position and into i on ln position rohrY 10T energizes circuit extending;- iiroin battery its right-hund winding, the lower contact oit cani 103 (T to 7%), the lower conos of cani 100 and thence to ground -iouuh the alternate Contact and righthand armature ot relay 10i and the lower c( ,ict ot cani 13.1. Relay 10T, upon ener f1, closes a ef cuit 'for driving .sequence i 110 out ot position 'i' und into posiwhieh circuit nay be traced i'roni ry throirglgh the inaggnet vinding of the @e switch, the upper lei't--hund cono'r cani 111 the inner right-hand alture and alternate contact ot relay 10i'` er contact olf cuni 112 ('T to 3) and frioind at the right-hand arnuiture iontact o'l'Y relay 102.

the ernnnas. or i the han ,7i/anfing' at Hee district' selector.

soon as sequence switch 110 leaves is, has no open Coiifliictoisi,

contact of relay 123, Wipe? 125, conclnctoi` 334, concluctoi` 335, resistance element 363, the Contact of cani 3518 (l to Tl) Winding oit relay 3&9, conductor 350, the Contact of coin L44 (9% to l0), the outer lett-lian@ ernieturevfincl loecl conte ct' ol ielif* ell; coiclvctor 35i., couiluetoi il b ,conc uctor lo@T ie on el coolicMJ oi cien 'l5/i" and thence to lriiieli ci-onli tested is in propel* pegzi, n lion, ilizit 3110 energygizes and at its filnnituie c circuit over conductor 'loienei'g'izing; ielay 4183. Relay 323, upon elleLgipaing7 a circuit for advancing seciienc i into position 1L Wl eh f from cette l tlnoii of switch 400, coniliicto tact oli' class switch lower contact of eine i armature and cont"L et oit re' l local energizing circi it lay 407 which may lie u 'om thi-cogli the ifglit-lizincl olf (ll), concliictoi 4:00, windings oli ielz-iy :lOl/'1 unil mieli conconducto? 408, the Minotel-e tact of relay 09, the inneil le. 'tuteancl back contact oli ieziy Y element ll and thence to 5,. hand Contact of com 13 (ll). upon eneigizing closes eiieiit ing sequence switch 00 irte A on l2 which may be traced 'from battery tliioinrli the `magnet Winding of Sequence switeli i005 the lowei" leftlinncl Contact olf cani e30 (11% conductor 423, tlie arinatiie and Contact o i' i-elriy 40T, conclucto1 :incl thence to ground through the lower Contact of czi-mfl'll l1 to l2).

[now/zing oms/l Selection.

With Sequence switch 00 in poeition l2 a fundamental cii1 uit is establishes extendiiisg from the office sender to the incoming se .eel-oi; switch Wliieli nifty lue ti-Lcecl in part *ogn brush 'lfil o'i tlie cli tiict Selector over "ifef'ioiiely ti'aceil to eontliictoi o tl e contact ol cani 2336, conductor 33T, tlie le'lt-lian/l winding o' overflow relay fil-57, the left-lionel aifnietoie anflluztclz Contact et relay Q10-l' Vthe lowei1 Contact olf com to conductor flo, tlie windings of stenv v, P' .L O 'l e. nog relay e04, eoneoctoi 0o? conouctoi -ll0 tlio innec left-lio, nl a-i'maitiu'e iincl loneli contact ol relay lll, ine oft-lionel contacts of cam 4:58, conductor Sill and thence as pi'eyiously tiacecl to loius 156 of tlle die' iict selector. The current llo-c 'ng this cncnit is not in tlie propel clie-cti'on to operate tlie Qolaiizecl relay 457, but Sender Stepping relay 407, however, energizes in this circuit.

notion that tlie numerical ie ilefiiieil line in llll :xml

Jah l i, l mi l o i l loing; m

lead lili Jie'. 0. teriniiiil 0250 liaiiil'; Til` 'f y. venian-mi' l, tlie upper coiilmt (l l to 'aim -ell clic cin'fiiit und :at tile lowei cout-net of 'om incoming group Sci'cff'fon.

cli 4,00 iii position ll uit iiieiioiwly iineed A oli senile? Stepping; rei llelzi'y 40T. upon en es :1 circuit loi ille No. il lieiiie; yliirioil tlmt j tillifci'io i' lmp: Het tlie liuiiiliell o poiioii ll. 'llie ifiiviiit ol ro lo:A liaiccfl from lizitlei'y tin-oo li ol' relay 'HT 'flic :iiui-itiii'e :xml i et the No il counting i'elziy leali li-11% Fig. (l, the oiifiei 'liront Contact ol" ieln)v 010. iielztji' is enei' poil :it this time over 04.0 of lieiil; ll* .foul wiper (HL tei= olf lmfil-i 'lll of lille tlioiifeuiiils n.'ipei' lll, minluitox' (lll. the l "f-lieiiil conJ :et o"V com "i (l to lionel cominci' ol mlm obl i fiel i loo Final liras/Tt Selection.

lVith sequence switch 400 in position 16, the fundamental circuit above traced is again established through the windings of sender stepping relay 407 and the winding` of the control relay (not shown) ot the `tinal selector 190. U pon the energization oic relay 407 in this circuit, a circuit is established .tor the No. 1 counting relay 4.26 which may be traced trom battery through the winding of relay 426, the armature and back contact oit the No, 1 counting relay 427, lead 475, lead 645 Fig. 6, terminal 646 of the banlr H3 of the hundreds register lit, wiper 647, conductor 648, the lower righthandv contacts oi cams 446 and 418 and thence through the armature contact of relay 407 to ground at the lower contact of cani 413 (15 to'16). Relay 426 lool-rs up in the well-knownA manner through the winding of the upper No. 1 counting relay 427 andV .during the brush selection movement or' the .final selector 190 the counting` rela-ys operate in succession until the No. 0 countingI relay 429 energizes in parallel with relay 409, when the fundamental circuit is opened to arrest the selective movement of selector 190 and the circuit previously traced is established for advancingsequence switch 400 out ot position 16 into posi.- tion 17.

It at the time sequence switchA 400 reaches position 17 the calling subscriber has completed' dialing and the register steering' switch litik has adif'anced into position 9, a circuit is established' tor advancing sender sequence switch 400' out of position 17 into position 18, preparatory to controlling` linall tens selection. This circuitmay be traced from ground at` the inner right-hand armature of relay 313, conductor 507, wiper 506,

terminal 548 of banl: R81 o' switch' RS,

conductor 549, the lower contact ot class switch cam (4 to 7), conductor 360, the lower lett-hand contact ot cam 401 (17) and through the magnet winding of sequence switch 400 to battery.

It is to be noted in this connection that as soon as the calling subscriber completed the dialing of the units digit of the desired number, the steering switch lil-S was advanced into position 6, whereupon a circuit was established for advancing it into position 7, which may be traced from battery through the winding and armature contact of stepping magnet 524, conductors 525 and 526, wiper 527, bank terminal 550 ot bank RS4 conductor 551, the right-hand contacts of class switch cam 361, conductor 362, the Contact of cam 450, conductor 402, the left-hand armature and front contact of relay 329, conductor 331 and thence to ground at the armature contact of relay 535. Upon reaching position 7 switch RS is advanced into position 8 over a similar circuit en` tending through the wnding ot magnet 524, through wiper 527, banl; terminal 552, conductor 553, the lower lett-hand and upper right-hand contacts oit cam 361 and thence over the circuit previously traced to ground at the contact of relay 535 and the switch is further advanced into position 9 over wiper 527, terminal 554, conductor 555, the upper contacts of cam 361. and thence to ground over the circuit previously traced.

Final tous selection.

lVith sequence switch 400 in position 18, the fundamental circuit previously traced is established through the winding of the control relay (not shown) of final selector 190 and the windings of sender stepping relay 407. Relay 407, upon energizing, prepares a circuit for the No. 1 counting relay 426, it being assumfd that the calling subscriber has set the tens register T in position 1. The circuit oit relay 426 may be traced from battery through the winding of relay 426, the armature and back contact of the No. 1 counting relay 427, lead 475, lead 649 Fig. 6, terminal 650 of bank T3, wiper 651, conductor 652,'the right-hand contacts of cam 4.18 and thence to ground through the armature Contact of stepping relay 407 and the upper contact of cam 413 (17 to 18). Relay 426, upon energizing, locks up in the wellthrough the winding of the No. 1 counting relay 427 and during the tens selection movement of the iinal selector 190, the counting relays operate in succession until the No. 0 counting relay 429 energizcs in parallel with relay 409, when the fundamental circuit is opened to arrest the selective movement ot the final selector and relay 429 establishes a circuit for energizing relays 411 and 436.

The circuit oi' relays 411 and 436 may be traced from battery through the windings of these relays, conductor `452, the upper left-hand and lower right-hand contacts of cam 451 (18), conductor 440, the inner righthand armature and back contact of relay 421, conductor 441 and thence to ground at the armature conta-ct of No. 0 counting relay 429. Relay 436, upon energizing, closes a locking circuit for itseltl and for relay 411 which may be traced through the windings of these relays, the inner right-hand armature and front contact of relay 436 and thence over conductor 438 to ground at the upper contact of cam 338 3 to 15). Relay 436, upon energizing, connects ground tc conductor for maintaining relay 145 af the district selector energized after sequence switch 400 leaves position 18 and opens cani contact 430. Relay 411 at its outer rightllO hand armature and iront contact establishes a circuit which may be traced over conducva tor 453 and through the windings or rela, 454 and 404 to battery. A circuit is non established for advancing sequence suite/li 400 out oit position 18 and into position 2, the energization ol relays 411, 4536, 454 and 404 being thus effective to change the circuit-s or the sender to operate With sequence switch 400 in its second revolution. The circuit 'Tor advancing sequence switch 400 may new be traced from battery through the magnet Winding of switch 400, the upper left-hand contact of cam 430 (18 to 1), conductor 4527 the outer le'ftdiand armature and 'trout con.- tact of relay 454, conductor 455, the righthand Contact of cam (18 to 1), and thence to ground on conductor 425.

Final umts selection.

With sequence switch 400 in position 2, the fundamental circuit extending "trom control relay of the final selector through thewinding or the sender steiiiping relay 407 may be traced in part from brush 151 over the circuit previously traced to conductor 337, the lett-hand Windinev of relay 457, the left-hand armature and front contact of relay 404., he upper lett-hand contact of cam` 456 (2), conductor 400 the windings of sender stepping relay 40T, conductor 408, the armature and baclr contact of relay 409, conductor 410, the inner leftr hand armature and :front contact of relay 411, the upper right-hand and lower letthand contacts of cam 45S and thence over the circuit previously traced to brush 15G ot the district selector 150.

Relay 407 energiaes in this circuit and establishes a circuit tor the No. 2 counting' relay 414, it being` assumed that the eallinff: subscriber has set the units register U into position 2 in response to the dialing ot' the last numerical digit. The circuit or relay 414 may be traced Jfrom battery through the Winding; or .relay 414, the armature and. back contact ot the No. 2 eountir,` relayv 415, lead 410, lead 653 Fia. G, bank termin 654 ot bank U3, Wiper G55, conductor (37.6., the right-hand armature and baci: contact or" Wipe-out relay 364, conductor i165, the contacts of cam 45S, conductor 459, the inner right-hand armature and Ytrent cout act of relay 411, eonduotor 4&10 and thence :is previously traced through the armature coutact of stepping` relay 407, to fgroin'id at, the upper contact et cam 413 (1 to 2). Counting relay 414 in the Well-known manner locks up through the Winding; ot the No. Q counting relay 415 and during` the units lection movement or the final selector 190 the counting relays operate and lock up in succession until the No, 0 counting` relay energizes in parallel with relay 409, when the fundamental circuit is opened to arrest the selective movement of selector ,190 and the sequence switch 1,00 is advanced into position 4. The circuit' o1 sequence switch 400 may be traced troni battery thi-ouah the lniet Winding; oit switch A100, the upper ht-haud Contact of, erin 1li-l0 (2), the leftarmature and, lront contact ot relay y, conductoz1 10, conductor 441. thence to :round at the armature contact ot the No. 0

intiing rei-ay 20.

ice no staons digrituA have been dialed by the calling; subscrilier the No. 0 counting ""7 90 remains locked to canse secueiu'e switch 400 to adnince directly from posi tion Z 'i position 10. The locking; circuit ott relay 120 inav be traced troni batter)v througli the -Windings olt relays 429 und #120. the contact o cani 400 (3 to the outer lett-hand :zrnniture and front contrrt ot t i Li, conductor 455, the upper riafht-V hund and louer lett-hand. contacts of cani f to Si, conductor 401. conductor 551,

ne rigjhthand contacts of class switch cuni i561, conductor the upper contact of cani fi-F0 (2 to 10). conductor 402, the let`t-h=md armature and `trout Contact. oi relay IQd. i and thence to ground :it the outer lei'thand armature and trout Contact, of relay Tailleur] Selection.

units selection the sequence incoming; selector is advanced.

to rtufcrse i i uinlaniental circuit in the manner full)` i rilied in t e application ot F. r\. Si tarn` Serial Fo, -Li 9. hereinlreiiore reterred in and with the son/,ler sequence switch toll in position 10, both tl sender steiu'iingr rela); 40T and polarized orertlon' relay 15T euri ojiZe. Relay lla-7T euerrgiices :it this tinn since 403, the lower lett-hand contact of' cuni 430 (9 to 1 0) to ground ou ow ductor Mela/ij( 1 upon eiernizii'uf owl' the lun dainentai circuit estnhiishes :i circuit "or the No. (l counting' relay .rhich nniy he traced from battery through the windingT of' relaY 428, lead lead A103, the outer left-hund armature and front coi'itact oif .relay 421, the upper contact o't` run the lu'r-.rvture und iront contact o1 relay 407, conductor 423 and loo llo

lili) lilo 

